1. Field of the Invention
The present invention relates to a connecting material for connecting a certain object(s) to another object, and more particularly a connecting material for connecting a certain object(s) such as an electronic component(s) to another object such as a circuit board (or a substrate). Furthermore, the present invention relates to an electronic circuit board which is produced by using such connecting material, and to a method for producing the electronic circuit board, as well as a method for detaching a certain object (such as an electronic component) from another object (such as a circuit board) to which the object was connected.
2. Description of Related Art
Recently, it has been tried to recycle an electronic component which was connected to an electronic circuit board used for various electrical or electronic devices including a personal computer, a mobile phone and the like, in view of environmental protection and resource-saving. Additionally, a price of an electronic component which is mounted on an electronic circuit board has been increased with advancement of its performance, so that it is very important to reuse such an expensive electronic component in order to reduce a production cost of an electronic circuit board.
In a conventional recovering method of an electronic component for recycling the electronic component, a connecting portion which is formed of a connecting material such as a solder, and connects an electronic component to a circuit board, is mechanically removed or broken by heating a spent electronic circuit board, applying a blade or the like to a surface of the circuit board and moving the blade parallel to a plane of the circuit board so as to scrape the electronic component off the circuit board and recover the electronic component.
However, according to the conventional recycling method as described above, an impact against an electronic component is strong, and a lead (e.g. electrode) which is led out from the electronic component is deformed and/or damaged. The electronic component itself is sometimes damaged. It is necessary to repair this damaged electronic component for a purpose of reuse thereof, so that the conventional method leads to a larger cost for reuse, which is contrary to its aim. Furthermore, according to the conventional method as described above, electronic components are recovered in a condition where various electronic components, debris generated by destruction and the like are admixed together since all the electronic components mounted on the circuit board are scraped off the circuit board at a time. Currently, thus recovered electronic components are manually classified because classification is too complicated.
In order to make such electronic component recovery easier, a detachable connecting structure is disclosed in Japanese Patent Publication No. 3125043, which is obtained by attaching an intermediate member, in the form of a thin film, to an electronic component and/or a circuit board and connecting the electronic component to the circuit board by virtue of a solder, wherein the intermediate member expands through a reaction with hydrogen to become powder-like or flake off. For the intermediate member of this connecting structure, a hydrogen storage alloy is used. When the intermediate member absorbs hydrogen, it expands or becomes powder-like to destroy a connecting condition between the electronic component and the circuit board, and thereby the electronic component is detached from the circuit board. It is noted that technical particulars which are described in Japanese Patent Publication No. 3125043 and which are applicable to the present invention in relation to the present invention described below are incorporated herein by reference thereto.
In order to obtain such connecting structure, it is needed to form a thin film of a hydrogen storage alloy on an electronic component and/or a circuit board prior to forming a connection by virtue of a solder. For formation of the thin film, it is necessary to add a step of forming such thin film to a conventional process for producing an electronic circuit board. However, this additional step is not desirable because it increases a production facility cost and a production cost. There is a need for further improvement in recovery of an electronic component.